In harvesting of crops planted in multiple rows, it is known to use multiple row harvesting heads in a harvesting apparatus. Such multiple row heads enable simultaneous harvesting of crops greatly increasing the efficency of the operation. Because the distances between various rows may differ for different crops, and may even differ for different rows of the same crop, such as in different fields, the invention of adjustable multiple row heads for such harvesting has naturally evolved. Such adjustable heads typically fall into one of two categories. In a first type of multi-row head, the various row units may be adjustably spaced from one another by selectively sliding the units to one of a plurality of available positions. In a second type of adjustable multi-row harvesting head, the row units may be pivoted to specific predetermined locations, thereby to provide a number of predetermined spacings between the inlets to the row units.
Units of the first type are illustrated by U.S. Pat. No. 4,115,983 to Barnes et al., and U.S. Pat. No. 3,520,121 to Ashton et al. Units of the second type are illustrated by U.S. Pat. No. 4,084,396 to Fritz et al., and U.S. Pat. No. 4,086,749 to Greiner et al.
The prior art devices, however, suffer from a number of deficiences. None of the previously known multiple row harvesting units are capable of, or include, adjusting devices for achieving infinite adjustment and variation of the spacing between the multiple row unit. Without such infinitely variable adjustment, the multiple units are constrained to operate at predetermined spacings which may differ from actual row spacings found on a farm to be harvested. Also, the adjusting mechanism typically involves a plurality of nuts and bolts or similar fasteners that are apt to be lost or misplaced. Under circumstances where infrequent changes are made, the fasteners are likely to become difficult to loosen for adjustment costing the farmer valuable harvest time.
Additionally, the prior art devices tend to have bulky and cumbersome supporting frame structures for the head units or modules, tending to increase the cost of manufacture and weight of the assembly. Perhaps more imporantly, the frame structures previously known allow accumulation of grasses, weeds and other trash leading eventually to clogging of the crop gathering belts or chains. This is especially true of the harvesters having cantilever-type structures for pivotal modules, as shown in the Fritz et al '396 and the Greiner et al '749 patents.
Still further, the prior art devices tend to supply the forage to the cutting station within the harvester apparatus at different locations and orientations. For example, in the case of multiple row harvesters having slideably adjusted row units, the rear discharge portion of the row unit is slideably mounted, thereby varying the location of the point at which the forage is received by the harvester. To overcome such difficulties, pivotably adjustable multiple row units typically provide for pivoting of a row unit about the axis of a rear drive sprocket for a gathering belt or chain therein, as illustrated by the disclosure of Fritz et al U.S. Pat. No. 4,084,396 referenced above. In such structures, however, the discharge angle, or orientation, of the gathering means and a passageway formed thereby differs for different adjustments of the row unit. Thus, even for harvesters having feeding inlets fixed behind the row units, the provision of the harvested forage at different angles of attack leads to incomplete or difficult acceptance of the material by the harvester thereby leading to buildup of unaccepted forage adjacent the feeding openings therefor, and ultimately to jamming of the equipment.
There is thus a need for multiple row harvesting equipment having infinitely variable adjustments for the various row units thereof, as well as for such equipment having an improved support frame particularly adapted for combining with the adjustment mechanism and tending to remain trash-free and accept all of the forage gathered and severed.